Distributed optical structures designed by computed interference between simulated optical signals

Abstract

A method comprises: formulating simulated design input and output optical signals propagating from/to respective designed optical input and output ports as optical beams substantially confined by a planar optical waveguide; computing an interference pattern between the simulated input and output signals; and computationally deriving an arrangement of diffractive elements of a diffractive element set from the computed interference pattern. When the diffractive element set is formed in the planar optical waveguide, each diffractive element routes, between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal propagating in the planar optical waveguide that is diffracted by the diffractive element set. The input optical signal is successively incident on the diffractive elements.

1. A method, comprising:
 formulating a simulated design input optical signal propagating from a designed optical input port as an optical beam substantially confined in at least one transverse dimension by a planar optical waveguide; 
 formulating a simulated design output optical signal propagating to a designed optical output port as an optical beam substantially confined in at least one transverse dimension by the planar optical waveguide; 
 computing an interference pattern between the simulated input and output signals; and 
 computationally deriving an arrangement of diffractive elements of a diffractive element set from the computed interference pattern, so that when the diffractive element set is formed in the planar optical waveguide, each diffractive element set would route, between corresponding input and output optical ports, a corresponding diffracted portion of an input optical signal propagating in the planar optical waveguide that is diffracted by the diffractive element set, and so that the input optical signal would be successively incident on the diffractive elements. 
 
   
   
     2. The method of  claim 1 , further comprising forming the set of diffractive elements in the planar optical waveguide according to the derived arrangement. 
   
   
     3. The method of  claim 1 , wherein the planar optical waveguide comprises a slab waveguide, and the input and output optical ports are spatially separated. 
   
   
     4. The method of  claim 3 , wherein the input and output optical ports are positioned relative to the diffractive element set so that respective propagation directions of the input and output optical signals are separated by a beam crossing angle greater than about 30°. 
   
   
     5. The method of  claim 3 , wherein the input and output optical ports are positioned relative to the diffractive element set so that respective propagation directions of the input and output optical signals are separated by a beam crossing angle greater than about 60°. 
   
   
     6. The method of  claim 3 , wherein the input and output optical ports are positioned relative to the diffractive element set so that respective propagation directions of the input and output optical signals are separated by a beam crossing angle greater than about 150°. 
   
   
     7. The method of  claim 6 , wherein the diffractive element set functions to split an input optical signal in multiple output beams. 
   
   
     8. The method of  claim 6 , further comprising a second set of diffractive elements, wherein the diffractive element sets function to split an input optical signal into multiple output beams. 
   
   
     9. The method of  claim 1 , further comprising computationally deriving an arrangement of diffractive elements of a diffractive element set from the computed interference pattern, so that when the diffractive element set is formed in the planar optical waveguide, a second diffracted portion of the input optical signal is routed between the input optical port and a second output optical port, or a diffracted portion of a second input optical signal is routed between a second input optical port and the output optical port. 
   
   
     10. The method of  claim 9 , further comprising computationally deriving an arrangement of diffractive elements of a diffractive element set from the computed interference pattern, so that when the diffractive element set is formed in the planar optical waveguide:
 a second diffractive element set routes the second diffracted portion of the input optical signal or the diffracted portion of the second input optical signal; 
 the arrangement of the diffractive elements of the second diffractive element set is computationally derived from an interference pattern computed from interference between a simulated design input optical signal and a simulated design output optical signal; and 
 the diffractive element sets are overlaid. 
 
   
   
     11. The method of  claim 9 , further comprising computationally deriving an arrangement of diffractive elements of a diffractive element set from the computed interference pattern, so that when the diffractive element set is formed in the planar optical waveguide, the diffractive element set routes the second diffracted portion of the input optical signal or the diffracted portion of the second input optical signal,
 wherein the arrangement of the diffractive elements of the diffractive element set is computationally derived from an interference pattern computed from interference between a simulated design input optical signal, a simulated design output optical signal, and a second simulated design input optical signal or a second simulated design output optical signal. 
 
   
   
     12. The method of  claim 1 , wherein the arrangement of the diffractive elements of the diffractive element set is computationally derived at least in part from a phase function of an interferogram of the interference pattern. 
   
   
     13. The method of  claim 12 , wherein the arrangement of the diffractive elements of the diffractive element set is derived from the phase function of the interferogram with a spatially-invariant intensity function thereof. 
   
   
     14. The method of  claim 12 , wherein each element of the diffractive element set is defined with respect to a constant-phase-difference contour of the phase function of the interferogram. 
   
   
     15. The method of  claim 14 , further comprising forming the set of diffractive elements in the planar optical waveguide according to the derived arrangement, wherein elements of the diffractive element set comprise a binary refractive index modulation. 
   
   
     16. The method of  claim 14 , further comprising forming the set of diffractive elements in the planar optical waveguide according to the derived arrangement, wherein elements of the diffractive element set comprise more than two levels of refractive index modulation. 
   
   
     17. The method of  claim 14 , further comprising forming the set of diffractive elements in the planar optical waveguide according to the derived arrangement, wherein elements of the diffractive element set comprise a partially reflective boundary. 
   
   
     18. The method of  claim 12 , wherein the arrangement of the diffractive elements of the diffractive element set is derived from both the phase function of the interferogram and a spatially-varying intensity function thereof. 
   
   
     19. The method of  claim 18 , wherein the intensity function is proportional to a magnitude of the simulated design input optical signal, to a magnitude of the simulated design output optical signal, or to a product of the magnitudes of the design input and output optical signals. 
   
   
     20. The method of  claim 18 , wherein the intensity function is chosen to yield a desired spatial transformation upon routing the diffracted portion of the input optical signal between the input optical port and the output optical port. 
   
   
     21. The method of  claim 18 , wherein the intensity function is chosen to yield a desired spectral or temporal transformation upon routing the diffracted portion of the input optical signal between the input optical port and the output optical port. 
   
   
     22. The method of  claim 1 , wherein each of the simulated design input optical signal and the simulated design output optical signal comprises a continuous-wave optical signal. 
   
   
     23. The method of  claim 1 , wherein the simulated design input optical signal comprises a substantially transform-limited optical pulse, and the simulated design output optical signal comprises a Fourier transform of a desired spectral transfer function. 
   
   
     24. The method of  claim 23 , wherein the planar optical waveguide comprises a channel waveguide. 
   
   
     25. The method of  claim 1 , wherein the simulated design input optical signal emanates from a mechanism coupling an out-of-plane optical signal to the interior of a slab waveguide, and the simulated design output signal converges onto a mechanism coupling in-plane optical signals out of the slab waveguide.